In Vivo Preclinical Support Laboratory - The In Vivo Preclinical Support group provides support to the Biological Testing Branch through its testing of potential anticancer agents in vivo. New agents submitted to the DTP are evaluated in the hollow fiber assay to assess their potential for in vivo activity using minimal amounts of test material as well as a minimal number of animals. Agents that are active in this assay are then tested in appropriate rodent tumor models (e.g., xenografts in immunodeficient mice or rodent tumors in syngeneic mice) where the route of administration, dose, and dose schedules are examined, in addition to the antitumor effect. Along with efficacy studies, this group provides support to the Phase 0 and CBC initiatives through evaluation of the pharmacodynamic (PD) effect of compounds on tumors growing in rodent species. This group is an integral part of the DTP anticancer drug development effort, the Phase 0 PD marker validation effort, and the CBC in vivo efficacy evaluation pathway. Compound Formulation & Compound Screening - The Compound Formulation & Compound Screening group provides support to the Biological Testing Branch through its preparation of test agents for assessment in the in vivo efficacy models including the hollow fiber and xenograft studies. This group maintains an inventory of test agents and accurately weighs and solubilizes the test material for testing. In addition, they determine the solubility of test agents in proposed vehicles as needed. This group also provides the technical support for the new combination drug screening effort undertaken in 2008. These assays provide in vitro efficacy data from studies in which a clinically approved agent is combined with a second clinically approved agent or an agent in clinical trials. These assays are conducted in 3 distinct cell lines using 3 dose levels of each test agent.